LNA gain adaption based on received signal strength of signals conforming to different communication protocols

ABSTRACT

A first low noise amplifier (LNA) applies a gain to both (a) signals conforming to a first communication protocol and (b) signals conforming to a second communication protocol. A second LNA applies a gain to the signals conforming to the first communication protocol. A third LNA applies a gain to the signals conforming to the second communication protocol is provided. A first signal strength indicator corresponding to a signal strength of a first signal, conforming to the first communication protocol, is determined. A second signal strength indicator corresponding to a signal strength of a second signal, conforming to the second communication protocol, is determined. The gain of the first LNA is controlled based on (i) the first signal strength indicator and ii) the second signal strength indicator. The gains of the second and third LNAs are controlled based on the first and second signal strength indicators, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.13/285,978, entitled “Low Noise Amplifier Gain Adaption Based on aReceived Signal Strength Indication of Bluetooth and WLAN Signals,”filed on Oct. 31, 2011, now U.S. Pat. No. 8,254,866, which is acontinuation of U.S. application Ser. No. 12/410,021, entitled “LowNoise Amplifier Gain Adaption Based on a Received Signal StrengthIndication of Bluetooth and WLAN Signals,” filed on Mar. 24, 2009, nowU.S. Pat. No. 8,055,230, which claims the benefit of U.S. ProvisionalPatent Application No. 61/039,279, filed Mar. 25, 2008. All of theabove-referenced applications are hereby incorporated by referenceherein in their entireties.

BACKGROUND

The increase in the number of handheld platforms in the recent years hascreated a need to integrate multiple wireless networking technologies onone communication integrated circuit (IC). Of these, the two most widelyused wireless networking technologies are wireless local area network(WLAN) (a.k.a., Wi-Fi) and Bluetooth. WLAN and Bluetooth both occupy asection of the 2.4 GHz Industrial, Scientific, and Medical (“ISM”) band.

Bluetooth is an industrial specification that can be used for wirelesspersonal area networks (“PANs”). Bluetooth can be particularly usefulwhen transferring information between two or more devices that are neareach other in low-bandwidth situations. Bluetooth can be used to connectand exchange information between devices such as mobile phones, laptops,personal computers, hand-held computers, printers, digital cameras, andvideo game consoles. Common applications of Bluetooth can includewireless control of and communication between a mobile phone and ahands-free headset (e.g., a Bluetooth earbud), wireless networkingbetween computers for certain applications, and wireless communicationsbetween a computer and input and output devices (e.g., mice, keyboards,and printers). Bluetooth uses Frequency Hopping Spread Spectrum (“FHSS”)and is allowed to hop between 79 different 1 MHz-wide channels in theISM band.

WLAN refers to wireless technology based upon the IEEE 802.11 standardsgenerally used for local area networking. Common applications for WLANinclude internet access and network connectivity for consumerelectronics. WLAN generally uses the same radio frequencies asBluetooth, but operates using higher power, generally resulting in astronger connection that can cover a greater distance. WLAN uses DirectSequence Spread Spectrum (DSSS) instead of FHSS. Its carrier does nothop or change frequency, and is instead maintained on one channel thatis 22 MHz-wide. There is room for 11 overlapping WLAN channels in theISM band, but there is only room for three non-overlapping channels.This means that no more than three different WLAN networks may operatein close proximity to one another.

Because both WLAN and Bluetooth wireless technology share spectrum andcan often be located in close physical proximity to one another, thereis a likelihood that some interference will occur. While WLAN andBluetooth technology can continue to function during interference,increasing levels of interference can result in a slowing of the datarate as more packets need to be resent. In some conditions of extremeinterference, communications can cease altogether.

Although both WLAN and Bluetooth use the same un-licensed 2.4 GHz ISMband, the link layer protocol used for communication over each of thesetwo technologies is very different. This poses a difficult problem fordesigning integrated circuits (ICs) and external logic components thatare capable of running link layer protocols for both WLAN and Bluetooth.In other words, in order for the end-user to use both WLAN and Bluetoothon the same device simultaneously, these two technologies are requiredto coexist with each other both in time and frequency. Among others,appropriate Time Division Duplex (TDD) and RF isolation techniques aresought after to resolve this problem.

SUMMARY

In one embodiment, a method for controlling (i) a gain of a first lownoise amplifier (LNA) to be applied to both (a) signals conforming to afirst communication protocol and (b) signals conforming to a secondcommunication protocol, (ii) a gain of a second LNA to be applied to thesignals conforming to the first communication protocol, and (iii) a gainof a third LNA to be applied to the signals conforming to the secondcommunication protocol is provided. The method includes determining afirst signal strength indicator corresponding to a signal strength of afirst signal received from a first communication device, the firstsignal conforming to the first communication protocol, and determining asecond signal strength indicator corresponding to a signal strength of asecond signal received from a second communication device, the secondsignal conforming to the second communication protocol. Also, the methodincludes controlling the gain of the first LNA based on at least (i) thefirst signal strength indicator and ii) the second signal strengthindicator, controlling the gain of the second LNA based on at least thefirst signal strength indicator, and controlling the gain of the thirdLNA based on at least the second signal strength indicator.

In another embodiment, an apparatus comprises a radio frequency frontend configured to receive i) a first signal from a first communicationdevice, and ii) a second signal from a second communication device,wherein i) the first signal conforms to a first communication protocol,and ii) the second signal conforms to a second communication protocol.The radio frequency front end includes a first low noise amplifier (LNA)to process both (a) received signals conforming to the firstcommunication protocol and (b) received signals conforming to the secondcommunication protocol. The apparatus further comprises a communicationmodule including a second LNA to process received signals conforming tothe first communication protocol, and a third LNA to process receivedsignals conforming to the second communication protocol. Thecommunication module is configured to determine a first signal strengthindicator corresponding to a signal strength of the first signalreceived from the first communication device, and determining a secondsignal strength indicator corresponding to a signal strength of thesecond signal received from the second communication device.Additionally, the communication module is configured to control the gainof the first LNA based on at least (i) the first signal strengthindicator and ii) the second signal strength indicator, control the gainof the second LNA based on at least the first signal strength indicator,and control the gain of the third LNA based on at least the secondsignal strength indicator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary embodiment of a system architecture forcoexistence of Bluetooth and WLAN in an electronic device.

FIG. 2 is a block diagram illustrating a RF front-end architectureaccording to one embodiment.

FIG. 3 is a diagram illustrating a process for adapting maximum LNA gainin the RF front-end in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

The present invention relates to low noise amplifier (LNA) gain adaptionbased on a received signal strength indication of Bluetooth and WLANsignals. The following description is presented to enable one ofordinary skill in the art to make and use the invention and is providedin the context of a patent application and its requirements. Variousmodifications to the embodiments and the generic principles and featuresdescribed herein can be made. Thus, the present invention is notintended to be limited to the embodiments shown, but is to be accordedthe widest scope consistent with the principles and features describedherein.

The present invention is mainly described in terms of particular systemsprovided in particular implementations. For example, the system isdescribed for use with wireless local area network (WLAN). However, thismethod and system may operate effectively in other implementations. Forexample, the systems, devices, and networks usable with the presentinvention can take a number of different forms, such as use with Wi-Max(Worldwide Interoperability for Microwave Access) technology. Thepresent invention will also be described in the context of particularmethods having certain steps. However, the method and system operateeffectively for other methods having different and/or additional stepsnot inconsistent with the present invention.

FIG. 1 illustrates an exemplary embodiment of a system architecture forcoexistence of Bluetooth and WLAN in an electronic device. The system 10includes an electronic device 12, a Bluetooth peer 14 and a WLAN peer 16(which includes WLAN access points) 16. Electronic device 12 may be anydevice operative to utilize both Bluetooth and WLAN transmissions andreceptions. The electronic device 12 may be generally any portable,mobile, or hand-held wireless electronic device having Bluetooth andWLAN functionality collocated on the same device. Examples of suchelectronic devices include cellular handsets, battery-powered mediaplayers, portable gaming consoles, smartphones, personal digitalassistants (PDAs) and ultra-low-power computing platforms.

The electronic device 12 may include an antenna 18, a radio frequency(RF) front-end 20, a Bluetooth and WLAN system-on-a-chip 22 (hereinafterreferred to as SOC 22), and a host processor 24. The electronic device12 can utilize a shared antenna 18 to maintain a Bluetooth link 28 withthe Bluetooth peer 14, and to maintain a WLAN link 30 with the WLAN peer16. In other embodiments, more than one antenna can be used to providethe functionality of the antenna 18. The RF front-end 20 is coupledbetween the antenna 18 and the SOC 22, and the SOC 22 is coupled to thehost processor 24.

In one embodiment, the RF front-end 20 and the SOC 22 may provideintegrated Bluetooth baseband/RF and 802.11a/b/g WLAN for the electronicdevice 12. The SOC 22 acts as a communication module or transceiver forboth WLAN and Bluetooth. In one embodiment, the SOC 22 may incorporateLayer 3 networking support (TCP/IP+UDP) and has the ability to runsupplicants (e.g., which are IEEE 802.1x/WPA components used in clientstations for key negotiation, controlling roaming and IEEE 802.11authentication/association of the WLAN driver) natively, offloading WLANfunctionality from the host processor 24. The SOC 22 may also supportall Bluetooth profiles with an industry standard HCI interface, andhence, has the ability to run Bluetooth profiles natively, offloadingBluetooth functionality from the host processor 24. The SOC 22 can beconnected to the host processor 24 using either a unified host interfaceor independent host interfaces for WLAN and Bluetooth connections.

The SOC 22 includes transmit/receive (T/R) control logic 26 thatcontrols operation of the RF front-end 20 to permit substantiallysimultaneous transmitting and receiving of Bluetooth signals and WLANsignals, as described below. The T/R control logic 26 may be implementedas software, hardware, or a combination of both.

FIG. 2 is a block diagram illustrating the RF front-end architectureaccording to one embodiment, where like components from FIG. 1 have likereference numerals. Although the RF front-end architecture 20 is shownfor use in electronic device 12 in conjunction with a SOC 22transceiver, the RF front-end architecture 20 is also applicable todevices having other types of transceivers and collocated WLAN andBluetooth devices.

In one exemplary embodiment, the RF front-end architecture 20 mayinclude a switch 200, paths 202 a, 202 b and 202 c, a band pass filter(BPF) 208. The band pass filter (BPF) 208 may be coupled between sharedantenna 18 and the switch 200 and may function to filter input andoutput signals to a desired bandwidth. Paths 202 a, 202 b and 202 c maybe coupled between the SOC 22 and three transmit and receive (TX/RX)ports 204 a, 204 b and 204 c of the switch 200. Path 202 a and port 204a may be dedicated to the transmissions of WLAN signals (WLAN TX). Path202 b and port 204 b may be dedicated to simultaneous receptions of theBluetooth signals and the WLAN signals (BT-RX/WLAN RX). And Port 204 cis shown dedicated to the transmission of Bluetooth signals only, butcorresponding path 202 c may be dedicated to 1) transmissions only ofBluetooth signals (BT-TX) when a WLAN link is active, and 2)transmissions and receptions of the Bluetooth signals (BT-RX) when theWLAN link is active and in a power save state, and when the WLAN link isinactive.

The switch 200 may control which of the three paths 202 a, 202 b and 202c to connect to the antenna 18. In one embodiment, the switch 200 may beimplemented as a single pole triple throw switch (SP3T). The function ofthe switch 200 is controlled by signals C1, C2 and C3 from the T/Rcontrol logic 26 of the SOC 22. For example, C1 may cause the switch 200to select port 204 a, C2 may cause the switch 200 to select port 204 b,and C3 may cause the switch 200 to select port 204 c,

In one embodiment, the path 202 a, which is dedicated to WLANtransmissions only, may include a power amplifier (PA) 210 thatamplifies the WLAN transmissions. This is used to avoid WLAN transmitpower suffering too much loss before the actual analog transmissionsfrom the antenna 18.

In one embodiment, the path 202 b may include an amplifier and adivider. The amplifier comprises a low noise amplifier (LNA) 212,although a distributed amplifier could also be used, and the divider 214comprises a RF divider. The divider 214 allows the path 202 b to receiveWLAN signals as well as BT signals from the antenna 18, enabling the SOC22 to receive the WLAN signals and the BT signals simultaneously intime. Since the incoming WLAN and BT receive signals suffer signalstrength losses at the BPF 208, the switch 200, and the divider 214, theLNA 212 shared by the received Bluetooth and WLAN signals amplifies bothof the signals to compensate for the loss of signal strength. Thedivider 214 splits the amplified Bluetooth and WLAN signals output bythe LNA 212 onto a WLAN receive path 216 and a Bluetooth receive path218. The WLAN receive path 216 coupled to the SOC 22, while theBluetooth receive path 218 is used an input Path 202 c for Bluetoothreceptions. In one embodiment, the LNA 212 may amplify the receivedBluetooth signals and the WLAN signals by approximately 14 dB, while thedivider 214 may result in a loss of approximately a −3.5 dB on both theWLAN receive path 216 and a Bluetooth receive path 218.

In one embodiment, the LNA 212 may have two input controls, an enable(EN) signal 224 and a bypass signal 226, both originating from the T/Rcontrol logic 26. The enable signal 224 can both enable and disable theLNA 212, such that the LNA 212 can be switched OFF to reduce overallcurrent consumption of the RF front-end 20 whenever path 202 b is notselected. The bypass signal 226 may cause the Bluetooth signals and WLANsignals to pass through the LNA 212 without amplification when path 202b is selected, but no gain is desired. This is to avoid over-saturationof the WLAN and Bluetooth receive paths 216 and 218 within the SOC 22.

Paths 202 b and 202 c are further multiplexed using a switch 220, suchas a single pole dual throw (SPDT) switch. The switch 220 selects theBluetooth receive path 218 when the RF front-end 20 is receivingBluetooth signals on path 202 b, and selects the path 202 c when the RFfront-end 20 is transmitting Bluetooth signals. Signal D1 228 from theT/R control logic 26 controls the selection of the switch 220. Signal D1228 may be replaced by two separate (or derived) signals from the SOC 22because in the embodiment where the switch 220 comprises a SPDT switch,two discrete inputs are used, in which case, the other input to theswitch could be a logical NOT of the first input in some cases.

The output of the switch 220 may be coupled to a balun 222, which inturn is coupled to the SOC 22. A balun joins a balanced line (one thathas two conductors, with equal currents in opposite directions, such asa twisted pair cable) to an unbalanced line (one that has just oneconductor and a ground, such as a coaxial cable).

In one embodiment, the path 202 c serves three mutually exclusivefunctions. 1) When operating alongside the co-located WLAN peer 16 andassuming an active WLAN link 30, the path 202 c is dedicated forBluetooth transmissions only. 2) When operating alongside the co-locatedWLAN peer 16 and assuming an active WLAN link 30 but in power save state(i.e., a doze state), path 202 c is dedicated for both Bluetoothtransmissions and receptions. 3) When operating alongside the co-locatedWLAN peer 16 and assuming an inactive WLAN link 30 (e.g., WLAN isswitched OFF in device 12), path 202 c is used for Bluetoothtransmissions as well as receptions.

The logic to switch the ports 204 a, 204 b, and 204 c on the switch 200is within the T/R control logic 26 of the SOC 22. This logic isconfigurable depending upon the type of Bluetooth traffic, the type ofWLAN traffic, and on the individual state of each of the two co-locatedbluetooth peer 14 and the WLAN peer 16 devices. Table I shows a logicaltruth table that could be used to implement the control signals C1, C2,C3, and D1 during different WLAN and BT states, where X means does notmatter.

TABLE 1 WLAN TX WLAN TX WLAN RX WLAN RX BT awake BT OFF BT awake BT OFFC1 1 1 0 0 C2 0 0 1 1 C3 0 0 0 0 D1 X X X X Results Path Path Path Path202a 202a 202b 202b

The columns in Table I show which of the paths 202 a, 202 b, and 202 care used with the WLAN peer 16 either transmitting (Tx) or receiving(Rx), and also with the co-located Bluetooth peer 14 in either an Awakeor a turned Off state simultaneously.

TABLE 2 BT TX BT TX BT TX BT RX BT RX BT RX WLAN WLAN WLAN WLAN WLANWLAN awake sleep OFF awake sleep OFF SP3T 0 0 0 0 0 0 C1 SP3T 0 0 0 1 00 C2 SP3T 1 1 1 0 1 1 C3 SPDT 1 1 1 0 1 1 D1 Results Path Path Path PathPath Path 202c 202c 202c 202b 202c 202c

Similarly, Table 2 shows which of the paths 202 a, 202 b, and 202 c areused when Bluetooth peer 14 is transmitting (Tx) or receiving (Rx) andwith the WLAN peer 16 in either the Awake, Sleep or turned Off state.Awake states in the above two tables mean idle; in other words, thecollocated device is powered up but is not maintaining an active linkwith any nearby device.

Table 3 shows possible examples of port transitions in switch 200. Thetransitions occur only when the SOC 22 decides to move between paths.For example, the first port transition is a transition from Bluetoothtransmit to WLAN transmit. The reverse transitions also applyaccordingly in the reverse direction for all the shown combinations.

TABLE 3 BT_TX → BT_RX → WL_RX → WL_RX → WL_TX → WL_TX WL_TX BT_TX WL_TXWL_RX SP3T 0 -> 1 0 -> 1 0 -> 0 0 -> 1 1 -> 0 C1 SP3T 0 -> 0 1 -> 0 1 ->0 1 -> 0 0 -> 1 C2 SP3T 1 -> 0 0 -> 0 0 -> 1 0 -> 0 0 -> 0 C3 SPDT 1 ->X X -> X X -> 1 X -> X X -> X D1 Results Path Path Path Path Path 202cto 202b to 202b to 202b to 202a to Path 202a Path 202a Path 202c Path202a Path 202b

The following describes additional points about switch transitions. Inone embodiment, there are no switch transitions for Bluetooth receive toWLAN receive, and for WLAN receive to Bluetooth receive. This enablessimultaneous WLAN receive and Bluetooth receive, i.e., on-goingreceptions on one of these two paths 204 a or 202 c will not beinterrupted due to a higher priority receptions expected on the otherpath. In one embodiment, the default state of the switch 200 is path 202b. Thus, the switch 200 will switch to path 202 b if there are no otherpending requests for transmissions or receptions.

As described above, the RF front-end 20 has an LNA 212 that is externalto the SOC 22. In conventional devices, a LNA typically has a fixedgain, such as 14 dB for example. This fixed gain may affect WLAN andBluetooth performance when the Bluetooth peer 14 and/or the WLAN peer 16are located in proximity to the electronic device 12, which is aWLAN+Bluetooth combo device. Such proximity may saturate receivers inthe SOC 22 quicker than expected without the LNA 212 in place. Inaddition to the external LNA 212, the SOC 22 includes an internal WLANLNA 230 on the individual WLAN receive (WLAN RX) path 216 and aBluetooth LNA 232 on the Bluetooth receive (BT RX) path 218. The maximumgain on both of the internal LNAs 230 and 232 may be adjustable. Thesaturation by the LNA 212 needs to be avoided because if the Bluetoothreceiver becomes saturated due to the LNA 212 gain, the quality ofBluetooth device (e.g., a headset) may be directly affected. Similarly,if the WLAN receiver becomes saturated because of the LNA gain 212, thedata or the device connection on the WLAN link may be directly affected.

According to a further aspect of the exemplary embodiment, the SOC 22 isprovided with a LNA gain adaptation algorithm 234 that may be used tocontrol and change the LNA gain of the RF front-end architecture 20. TheLNA gain adaptation algorithm 234 may be implemented in software,hardware, or both. In one embodiment, the LNA gain adaptation algorithm234 utilizes the bypass signal 226 to adapt the gain of the LNA 212based on received signal strength indications of the Bluetooth signalsand the WLAN signals, as described below.

FIG. 3 is a diagram illustrating a process for adapting maximum LNA gainin the RF front-end 20 in accordance with an exemplary embodiment. Theprocess may include the LNA gain adaptation algorithm 234 determining aBluetooth received signal strength indication of Bluetooth signalstransmitted by a Bluetooth peer 14 (300), and determining a WLANreceived signal strength indication of WLAN signals transmitted by aWLAN peer 16 (302). Hereinafter, the received signal strengthindications will be referred to as RSSI for brevity. As is known in theart, RSSI is a measurement of the power present in a received radiosignal, which can be ascertained when a receiving device uses wirelessnetworking of the IEEE 802.11 protocol. In one embodiment, the RSSI isdone prior to Bluetooth and WLAN baseband signals reaching the LNA 212.RSSI output may be a DC analog level, or may be sampled by an internalADC and the resulting codes made available directly or via a peripheralor internal processor bus.

The LNA gain adaptation algorithm 234 compares the Bluetooth RSSI topredetermined Bluetooth signal strength threshold(s) to determine aBluetooth peer distance (304), and compares the WLAN RSSI topredetermined WLAN signal strength threshold(s) to determine a WLAN peerdistance (306). Examples of the Bluetooth signal strength threshold(s)and the WLAN signal strength threshold(s) include the following:

If Bluetooth RSSI>=X db, then the Bluetooth peer distance=Near

If Bluetooth RSSI<X db, then the Bluetooth peer distance=Far

If WLAN RSSI>=Y db, then the WLAN peer distance=Near

If WLAN RSSI<Y db, then the WLAN peer distance=Far

As described above, the Bluetooth and WLAN signal strength thresholdsmay include Bluetooth and WLAN RSSI values, e.g., “X” and “Y” as well asassociated Bluetooth and WLAN peer distance values or conditions, e.g.,“Near” and “Far”. When a Bluetooth or WLAN RSSI matches one of thepredetermined Bluetooth or WLAN RSSI values, e.g., “X” or “Y”, thecorresponding Bluetooth and WLAN peer distance value, e.g., “Near” or“Far”, is assigned to the Bluetooth or WLAN peer distance.

In an exemplary embodiment, predetermined Bluetooth and WLAN RSSI valuesmay be stored in a memory of the SOC 22 and may be configurable by auser. In another embodiment, the Bluetooth and WLAN peer distance valuesmay also be configurable. The Bluetooth and WLAN peer distance valuesare shown enumerated as, “Near” and “Far”. However, in an alternativeembodiment, the Bluetooth and WLAN peer distance values may beenumerated with numbers and/or stated as a range of numbers. Althoughonly two Bluetooth and WLAN peer distance values are shown, theBluetooth and WLAN signal strength thresholds may include any number ofRSSI values and distance values depending on the application.

Referring again to FIG. 2, the LNA gain adaptation algorithm 234controls the gain the LNA 212 applies to the Bluetooth signals and theWLAN signals based on the Bluetooth peer distance and the WLAN peerdistance (308). In an exemplary embodiment, the LNA gain adaptationalgorithm 234 controls the gain of the LNA 212 by instructing the T/Rcontrol logic 26 to toggle the bypass signal 226 between two settings,Bypass-Off and Bypass-On. The Bypass-On setting places the LNA 212 in abypass mode in which the Bluetooth signals and WLAN signals pass throughthe LNA 212 without a gain being applied. The Bypass-Off setting placesthe LNA 212 in a fixed gain mode in which a fixed gain is applied to theBluetooth signals and the WLAN signals. In one embodiment, the bypasssignal 226 may be set to the Bypass-On setting by default.

In a further embodiment, the LNA gain adaptation algorithm 234 can alsobe configured to use the bypass signal 226 to control the internal WLANLNA 230 and the Bluetooth LNA 232 to optimize the overall performance ofthe electronic device 12.

Table IV shows how four cases of WLAN and Bluetooth peer distancevalues/conditions determined through RSSI values can be used to controlboth external LNA gain as well as internal LNA gains.

TABLE IV Distance Distance Bypass of WLAN of BT signal Internal InternalPeer Peer to ext. LNA WLAN LNA BT LNA 1 Near Far Bypass OFF low gainhigh gain 2 Far Near Bypass OFF high gain low gain 3 Near Near Bypass ONlow gain low gain 4 Far Far Bypass OFF med/high gain med/high gain

In the first row of Table IV, when the WLAN peer distance is Near andthe Bluetooth peer distance is Far, the LNA gain adaptation algorithm234 toggles the bypass signal 226 to the Bypass-Off setting so that theLNA 212 is placed in a fixed gain mode to boost the WLAN and Bluetoothsignals. In response to the Bypass-Off setting, the T/R control logic 26may set the internal WLAN LNA 230 to low gain, and the internalBluetooth LNA 232 to high gain.

In the second row of Table IV, when the WLAN peer distance is Far andthe Bluetooth peer distance is Near, the LNA gain adaptation algorithm234 toggles the bypass signal 226 to the Bypass-Off setting so that theLNA 212 is placed in a fixed gain mode. In response to the Bypass-Offsetting, the T/R control logic 26 may set the internal WLAN LNA 230 tohigh gain, and the internal Bluetooth LNA 232 to low gain.

In the third row of Table IV, when the WLAN peer distance and theBluetooth peer distance are both Near, the LNA gain adaptation algorithm234 toggles the bypass signal 226 to the Bypass-On setting so that theLNA 212 is placed in bypass mode since the WLAN and Bluetooth signals donot require a gain. In response to the Bypass-On setting, the T/Rcontrol logic 26 may set both the internal WLAN LNA 230 and the internalBluetooth LNA 232 to low gain.

In the fourth row of Table IV, when the WLAN peer distance and theBluetooth peer distance are both Far, the LNA gain adaptation algorithm234 toggles the bypass signal 226 to the Bypass-Off setting so that theLNA 212 is placed in the fixed gain mode. In response to the Bypass-Offsetting, the T/R control logic 26 may set the internal WLAN LNA 230 to amedium or high gain, and the internal Bluetooth LNA 232 to a medium orhigh gain.

Bypass ON or OFF may have little impact on the overall currentconsumption of the electronic device 12 but an adaptable gain protectsthe WLAN and Bluetooth receive paths from being saturated even thoughthe peer transmitting device is very close.

A method and system for LNA gain adaption based on a received signalstrength indication of Bluetooth and WLAN signals has been disclosed.The present invention has been described in accordance with theembodiments shown, and there could be variations to the embodiments, andany variations would be within the scope of the present invention. Forexample, the present invention can be implemented using hardware,software, a computer readable medium containing program instructions, ora combination thereof. Software written according to the presentinvention is to be either stored in some form of computer-readablemedium such as memory or CD-ROM, and is to be executed by a processor.Accordingly, many modifications may be made without departing from thescope of the appended claims.

1. A method for controlling (i) a gain of a first low noise amplifier(LNA) to be applied to both (a) signals conforming to a firstcommunication protocol and (b) signals conforming to a secondcommunication protocol, (ii) a gain of a second LNA to be applied to thesignals conforming to the first communication protocol, and (iii) a gainof a third LNA to be applied to the signals conforming to the secondcommunication protocol, the method comprising: determining a firstsignal strength indicator corresponding to a signal strength of a firstsignal received from a first communication device, the first signalconforming to the first communication protocol; determining a secondsignal strength indicator corresponding to a signal strength of a secondsignal received from a second communication device, the second signalconforming to the second communication protocol; controlling the gain ofthe first LNA based on at least (i) the first signal strength indicatorand ii) the second signal strength indicator; controlling the gain ofthe second LNA based on at least the first signal strength indicator;and controlling the gain of the third LNA based on at least the secondsignal strength indicator.
 2. The method of claim 1, wherein:controlling the gain of the second LNA is further based on at least thesecond signal strength indicator; and controlling the gain of the thirdLNA is further based on at least the first signal strength indicator. 3.The method of claim 1, further comprising determining, based on thefirst signal strength indicator, a first distance value corresponding toa distance of the first communication device; and determining, based onthe second signal strength indicator, a second distance valuecorresponding to a distance of the second communication device; wherein:controlling the gain of the first LNA is based on at least (i) the firstdistance value and ii) the second distance value, controlling the gainof the second LNA is based on at least the first distance value; andcontrolling the gain of the third LNA is based on at least the seconddistance value.
 4. The method of claim 3, wherein: controlling the gainof the second LNA is further based on the second distance value; andcontrolling the gain of the third LNA is further based on the firstdistance value.
 5. The method of claim 1, wherein: controlling the gainof the first LNA comprises selecting a mode of operation of the firstLNA from at least two modes of operation of the first LNA; controllingthe gain of the second LNA comprises selecting a mode of operation ofthe second LNA from at least two modes of operation of the second LNA;and controlling the gain of the third LNA comprises selecting a mode ofoperation of the third LNA from at least two modes of operation of thethird LNA.
 6. The method of claim 5, further comprising: determiningwhether the first signal strength indicator meets a first threshold;determining whether the second signal strength indicator meets a secondthreshold; wherein: selecting the mode of operation of the first LNAcomprises selecting the mode of operation of the first LNA based on (i)whether the first signal strength indicator meets the first threshold,and (ii) whether the second signal strength indicator meets the secondthreshold; selecting the mode of operation of the second LNA comprisesselecting the mode of operation of the second LNA based on whether thefirst signal strength indicator meets the first threshold; and selectingthe mode of operation of the third LNA comprises selecting the mode ofoperation of the third LNA based on whether the second signal strengthindicator meets the second threshold.
 7. The method of claim 6, wherein:selecting the mode of operation of the second LNA is further based onwhether the second signal strength indicator meets the second threshold;and selecting the mode of operation of the third LNA is further based onwhether the first signal strength indicator meets the first threshold.8. The method of claim 7, wherein: selecting the mode of operation ofthe first LNA comprises: selecting a bypass mode in which the first LNAdoes not amplify the first signal and the second signal when (i) thefirst signal strength indicator meets the first threshold, and (ii) thesecond signal strength indicator meets the second threshold, selecting afixed gain mode in which the first LNA applies a fixed gain to the firstsignal and the second signal when either (i) the first signal strengthindicator does not meet the first threshold, or (ii) the second signalstrength indicator does not meet the second threshold; selecting themode of operation of the second LNA comprises: selecting a low gain modeof the second LNA when the first signal strength indicator meets thefirst threshold, selecting a high gain mode of the second LNA when (i)the first signal strength indicator does not meet the first threshold,and (ii) the second signal strength indicator meets the secondthreshold, selecting a medium gain mode of the second LNA when (i) thefirst signal strength indicator does not meet the first threshold, and(ii) the second signal strength indicator does not meet the secondthreshold; selecting the mode of operation of the third LNA comprises:selecting a low gain mode of the third LNA when the second signalstrength indicator meets the second threshold, selecting a high gainmode of the third LNA when (i) the second signal strength indicator doesnot meet the second threshold, and (ii) the first signal strengthindicator meets the first threshold, selecting a medium gain mode of thethird LNA when (i) the second signal strength indicator does not meetthe second threshold, and (ii) the first signal strength indicator doesnot meet the first threshold.
 9. The method of claim 1, furthercomprising setting the first LNA to a low power mode when a thirdcommunication device is (i) transmitting signals conforming to the firstcommunication protocol, or (ii) transmitting signals conforming to thesecond communication protocol, wherein the third communication deviceincludes the first LNA, the second LNA, and the third LNA.
 10. Themethod of claim 1, wherein setting the first LNA to the low power modecomprises turning the first LNA off.
 11. The method of claim 1, whereinthe first communication protocol is a wireless personal area network(PAN) protocol, and the second communication protocol is a wirelesslocal area network (WLAN) protocol.
 12. An apparatus, comprising: aradio frequency front end configured to receive i) a first signal from afirst communication device, and ii) a second signal from a secondcommunication device, wherein i) the first signal conforms to a firstcommunication protocol, and ii) the second signal conforms to a secondcommunication protocol, and wherein the radio frequency front endincludes a first low noise amplifier (LNA) to process both (a) receivedsignals conforming to the first communication protocol and (b) receivedsignals conforming to the second communication protocol; and acommunication module including a second LNA to process received signalsconforming to the first communication protocol, a third LNA to processreceived signals conforming to the second communication protocol, andwherein the communication module is configured to determine a firstsignal strength indicator corresponding to a signal strength of thefirst signal received from the first communication device, determining asecond signal strength indicator corresponding to a signal strength ofthe second signal received from the second communication device, controlthe gain of the first LNA based on at least (i) the first signalstrength indicator and ii) the second signal strength indicator, controlthe gain of the second LNA based on at least the first signal strengthindicator, and control the gain of the third LNA based on at least thesecond signal strength indicator.
 13. The apparatus of claim 12, whereinthe communication module is configured to: control the gain of thesecond LNA further based on at least the second signal strengthindicator, and control the gain of the third LNA further based on atleast the first signal strength indicator.
 14. The apparatus of claim12, wherein the communication module is further configured to:determine, based on the first signal strength indicator, a firstdistance value corresponding to a distance of the first communicationdevice; determine, based on the second signal strength indicator, asecond distance value corresponding to a distance of the secondcommunication device; control the gain of the first LNA based on atleast (i) the first distance value and ii) the second distance value;control the gain of the second LNA based on at least the first distancevalue; and control the gain of the third LNA based on at least thesecond distance value.
 15. The apparatus of claim 14, wherein thecommunication module is configured to: control the gain of the secondLNA further based on the second distance value; and control the gain ofthe third LNA further based on the first distance value.
 16. Theapparatus of claim 12, wherein the communication module is configuredto: control the gain of the first LNA at least by selecting a mode ofoperation of the first LNA from at least two modes of operation of thefirst LNA; control the gain of the second LNA at least by selecting amode of operation of the second LNA from at least two modes of operationof the second LNA; and control the gain of the third LNA at least byselecting a mode of operation of the third LNA from at least two modesof operation of the third LNA.
 17. The apparatus of claim 16, whereinthe communication module is configured to: determine whether the firstsignal strength indicator meets a first threshold; determine whether thesecond signal strength indicator meets a second threshold; select themode of operation of the first LNA based on (i) whether the first signalstrength indicator meets the first threshold, and (ii) whether thesecond signal strength indicator meets the second threshold; select themode of operation of the second LNA based on whether the first signalstrength indicator meets the first threshold; and select the mode ofoperation of the third LNA based on whether the second signal strengthindicator meets the second threshold.
 18. The apparatus of claim 17,wherein the communication module is configured to: select the mode ofoperation of the second LNA further based on whether the second signalstrength indicator meets the second threshold; and select the mode ofoperation of the third LNA further based on whether the first signalstrength indicator meets the first threshold.
 19. The apparatus of claim18, wherein the communication module is configured to: select the modeof operation of the first LNA at least by: selecting a bypass mode inwhich the first LNA does not amplify the first signal and the secondsignal when (i) the first signal strength indicator meets the firstthreshold, and (ii) the second signal strength indicator meets thesecond threshold, selecting a fixed gain mode in which the first LNAapplies a fixed gain to the first signal and the second signal wheneither (i) the first signal strength indicator does not meet the firstthreshold, or (ii) the second signal strength indicator does not meetthe second threshold; select the mode of operation of the second LNA atleast by: selecting a low gain mode of the second LNA when the firstsignal strength indicator meets the first threshold, selecting a highgain mode of the second LNA when (i) the first signal strength indicatordoes not meet the first threshold, and (ii) the second signal strengthindicator meets the second threshold, selecting a medium gain mode ofthe second LNA when (i) the first signal strength indicator does notmeet the first threshold, and (ii) the second signal strength indicatordoes not meet the second threshold; select the mode of operation of thethird LNA at least by: selecting a low gain mode of the third LNA whenthe second signal strength indicator meets the second threshold,selecting a high gain mode of the third LNA when (i) the second signalstrength indicator does not meet the second threshold, and (ii) thefirst signal strength indicator meets the first threshold, selecting amedium gain mode of the third LNA when (i) the second signal strengthindicator does not meet the second threshold, and (ii) the first signalstrength indicator does not meet the first threshold.
 20. The apparatusof claim 12, wherein the communication module is configured to set thefirst LNA to a low power mode when the front end is (i) transmittingsignals conforming to the first communication protocol, or (ii)transmitting signals conforming to the second communication protocol.